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Adverse drug reactions, Drug interactions, Drug discovery and clinical evaluation of new drugs.pdf

  1. Unit:-2 Adverse drug reactions By, Dr.Ravikiran.S Assistant Professor
  2. any noxious change which is suspected to be due to a drug. Be kind Definition:-
  3. Predictable reactions Unpredictable reactions Adverse effects have been classified in many ways. One may divide them into: 1. 2. 1. Predictable (Type A) reactions (mechanism based adverse reactions):- These are based on the pharmacological properties of the drug, which means that they are augmented, but qualitatively normal response to the drug; include side effects, toxic effects and consequences of drug withdrawal. 2. Unpredictable (Type B reactions:- These are based on peculiarities of the patient and not on drug’s known actions; include allergy. They are less common, often non-dose related, generally more serious and require withdrawal of the drug.
  4. SEVERITY OF ADVERSE DRUG REACTIONS HAS BEEN GRADED AS: Minor: No therapy, antidote or prolongation of hospitalization is required. Moderate: Requires change in drug therapy, specific treatment or prolongs hospital stay by atleast one day. Severe: Potentially life-threatening, causes permanent damage or requires intensive medical treatment. Lethal: Directly or indirectly contributes to death of the patient. 1. 2. 3. 4.
  5. Prevention of adverse effects to drugs Adverse 1. Avoid all inappropriate use of drugs in the context of patient’s clinical condition. 2. Use appropriate dose, route and frequency of drug administration based on patient’s specific variables. 3. Drug allergy is more common in patients with allergic diseases. 4. Rule out possibility of drug interactions when more than one drug is prescribed. 5. Adopt correct drug administration technique. (e.g. intravenous injection of vancomycin must be slow). 6. Carry out appropriate laboratory monitoring.
  7. Definition:- A drug interaction is a change in the action or side effects of a drug caused by concomitant administration with a food, beverage, supplement, or another drug. Main factors contributing to drug interactions are- Multiple drug therapy. Multiple pharmacological effects of drug. Multiple diseases / illness. Poor patient compliance. Advancing age of patient. Drug related factors.
  8. Types Of Drug Interactions Drug-drug interactions. Drug -food interactions. Drug-chemical interactions. Drug-laboratory test interactions. Drug-disease interactions. 1. 2. 3. 4. 5.
  9. 2 1 Pharmacokinetic Interactions:- Modifications in the effect of a drug are caused by differences in the absorption, transport, distribution, metabolism or excretion of one or both of the drugs compared with the expected behavior of each drug when taken individually. Pharmacodynamic Interactions:- When two drugs are used together, their effects can be additive (the result is what you expect when you add together the effect of each drug taken independently), synergistic (combining the drugs leads to a larger effect than expected), or antagonistic (combining the drugs leads to a smaller effect than expected).
  10. Drug discovery and clinical evaluation of new drugs UNIT:- 2
  11. The process by which new candidate medications are discovered is called as Drug Discovery System. Defination
  12. Preclinical trial - a laboratory test of a new drug or a series of chemicals, usually done on animal subjects, to see if the hoped for treatment really works and if it is safe to test on humans. Preclinical evaluation
  13. A type of research that studies new tests and treatments and evaluates their effects on human health outcomes Clinical trail:-
  14. 1 2 3 Phase I On Health person Possible harm Side effects Dosage Phase II On Patient Side effects & Efficacy On Patient Efficacy & Adverse reactions Phase III Phases of clinical trail 4 Phase IV Post marketing surveillance In different groups of people And/or in combination with other treatments
  15. Opportunities for questions should be provided before each vaccination Vaccine. Information Statements. Must be provided before each dose of vaccine.. Public and private providers. Available in multiple languages. 1. 2. 3.
  16. Phase- I Phase- I Generally, in Phase I trials, the healthy volunteers have been selected. In this trial, a small number of volunteers (20-50) are selected for the study. Generally, this phase has been conducted in order to analyze the safety, tolerance, pharmacodynamic and pharmacokinetic properties of a drug. These trials are often performed in clinical centres where the subjects are kept under observations by full–time staff. Generally, in this study, a group of patients have been administerd the multiple low doses of the drug, while samples are collected at various time intervals and analyzed in order to collect information regarding the processing of drug inside the body. Later on, the dose of the test drug is increased for further groups upto a certain level in such studies.
  17. People affected by the disease and Sample size is 50-100 patients. To check the Side effects and Efficacy. PHASE- II PHASE- II The doses used in phase 2 are generally less than the highest of those used in phase 1. Phase II trials are performed at special clinical centers like that of universities and hospitals.
  18. To analyze the efficacy of new drug and its therapeutic effect in clinical practices. Phase III trials have been considered as the most expensive, time consuming and difficult to design and run. Phase III are continued until the regulatory submission is pended at the appropriate regulatory agency. To find any Adverse reactions find. Compared to other treatments. These studies involve 100 to 1,000 participants. Phase- III
  19. PHASE IV:- Also referred to as “Post marketing surveillance”. The Phase IV studies can be performed with the help of regulatory authority or by sponsoring company for finding a new market of the drug. Such trails have been designed to find out if any long term adverse effect over a much large population of patients for a longer period of time. Any one seeking treatment for their physician and Watch drug long term effect. dr_ravikiran_
  20. Pharmacovigilance The information generated by pharmacovigilance is useful in educating doctors about ADRs and in the official regulation of drug use. It has an important role in rational use of medicines, as it provides the basis for assessing safety of medicines. Introduction:- Pharmacovigilance has been defined by the WHO as the ‘science and activities relating to the detection, assessment, understanding and prevention of adverse effects or any other drug related problems. Defination:-
  21. THE ACTIVITIES INVOLVED IN PHARMACOVIGILANCE ARE: Postmarketing surveillance and other methods of ADR monitoring such as voluntary reporting by doctors (e.g. yellow card system of UK). Voluntary reporting depends on the initiative and willingness of the health professionals. It is minimal in India, while even in the developed countries only ~10% ADRs are reported voluntarily. Generally, immediately occurring reactions and those that are dramatic are reported. Though even rare reactions can be detected by this method, it does not provide incidence of the reaction. Presentations are tools that can be used as lectures, speeches, reports, and more. It is mostly presented before an audience Dissemination of ADR data through ‘drug alerts’, medical letters,’ advisories sent to doctors by pharmaceuticals and regulatory agencies (such as FDA in USA, committee on safety of medicines in UK). Changes in the labelling of medicines indicating restrictions in use or statuary warnings, precautions, or even withdrawal of the drug
  22. MORE ABOUT PHARMACOVIGILANCE Pharmacovigilance center's have been set up in most countries. The Uppsala Monitoring Centre (Sweden) is the international collaborating centre. In India, the national coordinating centre is located in the All India Institute of Medical Sciences. Regional centres are expected to collect and communicate. ADR data by linking with medical institutions and practitioners. The pharmacovigilance centres are also expected to provide expertise for assessing causality and severity of ADRs by using standard algorithms and rating scales. 1. 2.
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